The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, various different methods and circuits were used to assist in determining the operational status of circuits used to form redundant power supply systems. Multiple power rectifiers, such as ORing diodes or power MOS transistors controlled to operate as a diode, often were used to allow the multiple power sources to supply power to a load. In some cases, the rectifiers would fail and such failure sometimes was not detected until the rectifier was needed for operating the power system. Previous tests circuits used to determine the operational status of the rectifiers generally could only determine an open condition of the rectifier in the forward biased operating mode. Other failure states generally could not be evaluated while the rectifiers were in use within the power system.
Accordingly, it is desirable to have a test circuit that can determine the operational state of a rectifier during the operation of the rectifier, and that can determine failure states other than an open condition in the forward biased mode.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action.